How an Overgrowth of Fungus in Children’s Intestines Could Explain ADHD Symptoms

Researchers found an overgrowth of a certain fungus in children with ADHD. And this imbalance of the intestinal flora could explain why these children have an attention disorder.

The human gastrointestinal tract is home to an immense population of microorganisms, such as bacteria, viruses and fungi. And make no mistake, it is a collection of truly trillions of microbes, each of which has an important job. Scientists have suspected for some time that this diligent intestinal population is not only important for digestion, but also exerts influence in many more areas. In fact, into a new study researchers have found evidence showing that gut microbial composition may influence a child’s susceptibility to ADHD.

What is ADHD?
ADHD (Attention Deficit Hyperactivity Disorder) is a neurodevelopmental disorder. Children with ADHD are easily distracted and have difficulty concentrating. They are very busy (hyperactive) and often do things without thinking (impulsive). This can lead to problems within the family, at school and in social interactions. According to the World Health Organization (WHO), 5 to 8 percent of children are diagnosed with ADHD. There is no treatment or medicine for a cure, but there are means and therapies to combat the symptoms. The best known drug is Ritalin, with the active ingredient methylphenidate. The sleep hormone melatonin is sometimes prescribed for sleep problems.

In the study, the researchers compared the stools of 35 children with ADHD with those of 35 children without an attention disorder. And that shows a clear difference in gut microbiomes (the composition of microbes that live in the intestines).

Candida albicans
One species of mold was remarkably abundant in the stools of the children with ADHD. It’s a fungus Candida albicans is called. “This fungus occurs naturally in the intestines, on the skin and in the mucous membranes,” said researcher Liang-Jen Wang in conversation with Scientias.nl. “However, an overgrowth of this fungus may be associated with intestinal disorders or unhealthy dietary habits.” The researchers do not know why children with ADHD harbor higher numbers of this fungus. But it is disturbing.

Leaky gut
This is mainly due to the fact that an excess of Candida albicans damages the intestinal mucosa in the intestines. This creates ‘holes’ in the intestines, which researchers also call a ‘leaky gut’. “In our study, we not only proved that children with ADHD are more Candida albicans but that an overabundance of this fungus also leads to leaky gut,” says Wang. The consequences of a leaky gut can be far-reaching. Bacteria find their way into the bloodstream through these ‘perforated’ holes, which can potentially lead to nasty inflammation throughout the body – including the brain.

Dysbiosis
The researchers suspect that a so-called dysbiosis has developed in children with ADHD; a disturbance of the balance of the intestinal flora. “The human body is home to a complex and diverse microbial ecosystem,” says Wang. “And our study now shows that dysbiosis of the microbiome due to a fungus can affect mental health. Possibly the increased intestinal permeability, caused by an abundance of Candida albicansa role in the development of ADHD.”

Brain-gut axis
It means that ADHD, one of the most common neurodevelopmental disorders, may be the result of a dysregulated gut flora. And that, according to Wang, is not so far-fetched. “The ‘brain-gut axis’, referring to the relationship between gut function, gut microbial composition and the central nervous system, has been suggested to influence several neuropsychiatric disorders,” explains Wang. “In addition, dysbiosis, which refers to a marked dysfunction observed in the gut-brain axis during development, is suspected to be associated with neurodevelopmental disorders.”

More about the brain-gut axis
The brain-gut axis indicates a strong connection between the gut flora and the brain. These two would actually communicate with each other non-stop. The brain-gut axis actually refers to a two-way connection between the cognitive and emotional centers of the brain and the functioning of the gut. Scientists describe this as a bidirectional communication between the enteric nervous system (the gut) and the central nervous system (the brain). It is suggested that this connection is involved in the origin and/or development of various human disorders. This could be related to physical connections through millions of nerves, disruption of the gut microbiome, and the production and release of various chemicals (or neurotransmitters) in the gut.

It means that gut microbes may therefore influence the development of ADHD. But this is not all bad news. This also makes it treatable. According to the researchers, it is possible to restore the intestinal microbiome of children, in order to reduce the symptoms. “Rebalancing the gut microbiota can significantly improve ADHD symptoms,” says Wang. “Several clinical studies have shown that taking probiotic supplements can be very beneficial for people with ADHD.”

Investigation of the suggested link between the fungus Candida albicans and ADHD continues. “In a follow-up study, we would like to investigate in more detail in which ways Candida albicans may increase the risk of ADHD,” says Wang. “For example, we want to see how the toxic elements excreted by the fungus damage the intestinal mucosa. We also want to study whether these can enter the human bloodstream and even the central nervous system, and thus influence neural development.”